T1-weighted dynamic contrast enhanced magnetic resonance imaging (“DCE-MRI”) can be an important procedure for diagnosis, and for assessing treatment response of cancer (see, e.g., References 1-4), as well as for various inflammatory diseases, such as multiple sclerosis (see, e.g., Reference 5), rheumatoid arthritis (see, e.g., Reference 6), and inflammatory bowel diseases. (See, e.g., References 7 and 8). Time-intensity curves of DCE-MRI can contain rich information about the tissue microcirculation environment, and can be analyzed using contrast kinetic models to estimate physiologically relevant parameters, such as a transfer constant (e.g., Ktrans), plasma volume fraction (e.g., vp), and extravascular extracellular space volume fraction (e.g., ve). (See, e.g., References 9 and 10). However, quantitative analysis of DCE-MRI data remains challenging, particularly due to the need to separately measure the pre-contrast longitudinal relaxation time constant (e.g., T10) of the tissue (see, e.g., Reference 9) and actual flip-angles (“FA”) achieved for T1 measurement and the dynamic scan. (See, e.g., References 11-13).
The degree of contrast enhancement in a tissue can vary depending on the T10 of the tissue, such that analyses of DCE-MRI data based on time-intensity curves without taking into account the T10 variability in lesions can result in a limited diagnostic accuracy. (See, e.g., Reference 14). For a more robust quantitative analysis, DCE-MRI time-intensity curves can be converted to contrast agent concentration curves. Such signal-to-concentration conversion process can utilize T10 values, which can be measured using various methods, such as inversion recovery (see, e.g., Reference 15 and 16) and variable flip angle methods (see, e.g., Reference 17), but at the cost of extra scan time. In addition, accurate T1 mapping can typically utilize correction for the inhomogeneous radiofrequency (“RF”) transmit field (e.g., B1). (See, e.g., References 11 and 18-20). B1 field maps can also be used to correct for the B1 inhomogeneity effect in the T1-weighted DCE-MRI data itself. Various B1 mapping methods have been developed based on either magnitude images (see, e.g., References 21-23) or phase images (see, e.g., References 24-26) which can be made sensitive to the B1 field. Most B1 mapping methods utilize either a long repetition time (“TR”) to minimize the tissue T1 effect, or an extra measurement of B0 field to minimize the off-resonance effect, which can lead to a further increase of the scan time. Furthermore, there can be other factors that can also affect the actual FA, such as slice profile (see, e.g., Reference 27) and RF amplifier nonlinearity. (See, e.g., Reference 28). The scan time needed for these additional measurements of T10 and FA correction factor (f) can often be similar to, or longer than, the actual DCE-MRI scan itself (See, e.g., References 11 and 29). Given a limited scan time available in most clinical scans, it may not be trivial to conduct a quantitative DCE-MRI experiment with appropriate T10 and f measurements. Thus, in order to utilize the full potential of DCE-MRI as a clinical and research tool, it can be beneficial to improve the means to accurately measure and/or correct for T10, and other factors affecting FA, without substantially increasing the total scan time.
Fast B1 mapping has been evaluated for many quantitative MRI measurements, including DCE-MRI, as B1 non-uniformity can be one of the main causes of difference between the nominal FA and actual FA. B1 mapping can be performed using either the magnitude or phase of magnetic resonance (“MR”) images that can reflect the B1 field strength. There are several B1 mapping techniques based on the magnitude images, such as finding the signal null at a FA of 180° (see, e.g., Reference 23), or calculation of the signal ratio from images with two FAs. (See, e.g., References 21 and 22). Since the image magnitude can depend on T1 of tissue and TR, the magnitude-based methods typically utilize a long TR (e.g., >about 5T1) to eliminate the T1 dependence (see, e.g., Reference 21), which can lead to a long scan time. In order to reduce the scan time, fast imaging methods with extended echo-train-length (see, e.g., References 38 and 39), or echo-planar imaging (see, e.g., References 40 and 41), have been used, in addition to employing a means to minimize the effect of not-fully recovered longitudinal magnetization by playing out special RF pulses at the end of the sequence. (See, e.g., References 41 and 42). The phase-based B1 mapping methods use either composite excitation pulse (see, e.g., Reference 24) or an excitation pulse followed by an off-resonance Bloch-Siegert Shift pulse (see, e.g., References 25 and 26), in order to sensitize the phase of the images to the B1 field strength. One of the challenging issues with the phase-based methods can be the influence from the B0 inhomogeneity that can bring a need for additional B0 field mapping at the cost of additional scan time, or careful advanced design of RF pulse. In the case of the Bloch-Siegert Shift method, RF power deposition in the tissue can be another constraint as the measurement accuracy improves with the Bloch-Siegert Shift pulse power. Thus, while these recent developments offer a number of different ways to measure B1 field map, acquiring B1 map during clinical scans still remains technically challenging and an extra burden of scan time and warrants further development.
Thus, it may be beneficial to provide exemplary system, method and computer-accessible medium that can be used to measure both f and T10 values, along with kinetic model parameters from dynamic scan data, without having to run additional scans for separate measurement of f and T10, and which can address and/or overcome at least some of the deficiencies described herein above.